The Agency for Natural Resources and Energy and electric power companies in Japan decided to revise the renewable energy full-amount purchase system on November, 2014. The reasons and measures are as follows.
(1) In order to maintain operation with stable system interconnection (in voltage, frequency, and phase), it is necessary to suppress power generated from renewable energy to less than 50% of the value of instantaneous power generated (the instantaneous demand value from the perspective of the power consuming side).
(2) If this is not complied with and electric power companies' thermal power plants fail to cover an abrupt change in the power generated from renewable energy (an event such as stoppage of power generation) due to the weather condition and the like, the consequence can be a major power outage (blackout) over a wide area.
(3) According to “the Ministerial Ordinance and the Related Public Notices for Partially Revising the Ordinance for Enforcement of the Act on Special Measures Concerning Procurement of Electricity from Renewable Energy Sources by Electricity Utilities” by the Agency for Natural Resources and Energy, announced on Jan. 22, 2015, a trend of “unlimitedly generated power (which varies depending on the scale of the power generation)” seems to be inevitable for stabilization of power grids. This is leading to a slump in renewable energy power generation businesses based on private investment aiming to gain profits from selling generated power. However, this procedure seems unavoidable for stabilization of power grids. Further, this notice states that “it is essential for Japan to introduce a more effective and meticulous output-control scheme so as to successfully introduce renewable energy per kWh to the maximum extent possible”.
Because of this, solar panel manufacturers have been demanded to newly provide output limiting functions and attempting to develop techniques by the end of fiscal year 2015.
Thus, the situation is that new businesses are practically difficult to establish until these conditions are met.
(4) The Agency for Natural Resources and Energy and electric power companies have authorized resumption of businesses on condition that past calendar information (non-business days and holidays in summer time) is stored on a server and the power producer accepts performing output suppression based on scheduled (predictive) control (entirely at the power producer's expense).
In this case, however, the output suppression is performed even on the actual day where the output suppression is not necessary since it is based on past weather information. This is disadvantageous economically and in view of CO2 reduction and has drastically reduced power producers planning to go into the business again even by satisfying these strict conditions.
(5) Despite this situation, Japan has announced a proposed policy to increase the proportion of renewable energy such that the proportion will be twice (20%) greater the current one by around 2025. However, due to the above-described conflict, there has been a demand for new techniques.
Meanwhile, Patent Document 1 is a target value setting type demand power proportional control device for smoothly controlling power for a load side (power consuming side) for air conditioning in order to stabilize a power grid. The device outputs a control signal for controlling the power consumption of all loads to a target value, only to air conditioners including exhaust equipment, which are automatically controllable loads. This offers the advantage that it is possible to avoid decrease in production efficiency of production machines, which are not included in the automatically controllable loads, and also to freely control the power consumption of the business facility toward any target value.